Molecular design of hybrid tumor necrosis factor-alpha III: polyethylene glycol-modified tumor necrosis factor-alpha has markedly enhanced antitumor potency due to longer plasma half-life and higher tumor accumulation

We have reported that chemical modification of tumor necrosis factor-alpha (TNF-alpha) with polyethylene glycol (PEG) markedly increases its antitumor potency without any adverse side effects. MPEG-TNF-alpha, especially, in which 56% of the lysine amino groups of TNF-alpha are coupled with PEG, exhibits 100-fold more antitumor activity in vivo than native TNF-alpha in the Meth-A murine sarcoma model. In this study, we investigated the pharmacokinetics of PEG-modified TNF-alpha with various molecular sizes to clarify the mechanisms of the enhanced antitumor potency of MPEG-TNF-alpha. The plasma half-lives of modified TNF-alpha increased with increasing molecular size. The decreased plasma clearance of modified TNF-alpha was partially caused by the shielding effect of the proteolytic sites in TNF-alpha by the attached PEG and the decreased transport from blood to various tissues. Almost all native TNF-alpha was uniformly distributed to the kidney and reticuloendothelial system within 1 hr of an intravenous administration, and rapidly disappeared from these tissues at 3 hr. However, very little native TNF-alpha was transported into the tumor. The absolute distributed amount and distribution profile of modified TNF-alpha to tissues other than the tumor were the same as those of native TNF-alpha, whereas the plasma levels of the modified TNF-alpha were higher than plasma levels of the native TNF-alpha. The tumor distribution of modified TNF-alpha was markedly enhanced compared with native TNF-alpha and gradually increased over time. About 9-fold more MPEG-TNF-alpha was distributed to the tumor than native TNF-alpha. Thus, we found that the marked increase in the antitumor potency of PEG-modified TNF-alpha resulted from the enhanced blood residency and tumor accumulation. The antitumor effect of MPEG-TNF-alpha against sarcoma-180 other than Meth-A fibrosarcoma was also about 100 times greater than that of native TNF-alpha when systemically administered. The optimal PEGylation of TNF-alpha facilitated its antitumor potency and MPEG-TNF-alpha may be useful systemic antitumor therapeutic drug.     

Dopamine as a novel antimigration and antiproliferative factor of vascular smooth muscle cells through dopamine D1-like receptors

Vascular smooth muscle cell (VSMC) migration and proliferation are believed to play key roles in atherosclerosis. To elucidate the role of vascular dopamine D1-like receptors in atherosclerosis, the effects of dopamine and specific D1-like agonists SKF 38,393 and YM 435 on platelet-derived growth factor (PDGF) BB-mediated VSMC migration and proliferation were studied. We observed that cells stimulated by PDGF-BB (5 ng/mL), showed increased migration and proliferation. These effects were prevented by coincubation with dopamine, SKF 38,393, or YM 435 (1 to 10 mumol/L), and this prevention was reversed by Sch 23,390 (1 to 10 mumol/l), a specific D1-like antagonist. These actions are mimicked by forskolin (1 to 10 mumol/L), a direct activator of adenylate cyclase and 8-bromo-cAMP at 0.1 to 1 mmol/L and are blocked by a specific protein kinase A inhibitor, N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinoline-sulfonamide (H 89), but not blocked by its negative control, N-[2-(N-formyl)-p-chlorociannamylamino)ethyl]-5-isoquinoline sulfonamide (H 85). PDGF-BB (5 ng/mL)-mediated activation of phospholipase D, protein kinase C, and mitogen activated protein kinase activity were significantly suppressed by coincubation with dopamine. These results suggest that vascular D1-like receptor agonists inhibit migration and proliferation of VSMC, possibly through protein kinase A activation and suppression of activated phospholipase D, protein kinase C, and mitogen-activated protein kinase activity.     

原爆存活者染色体畸变的生物学意义

本文报告了关于广岛原爆存活者骨髓细胞(105例)和外周血 T 淋巴细胞(39例)、B 淋巴细胞(4例)的细胞遗传学变化以及发生慢性粒细胞白血病和乳癌的两例病人定期检查的细胞遗传学结果。骨髓细胞染色体畸变分析表明,距离下爆心0.5km 以内和0.5—1 km 的受照者分别有90%和52.4%出现染色体畸变,染色体畸变细胞分别占观察细胞总数的23.2%和12.8%,每一组都有7例出现异常克隆(Clone)。出现的畸变类型大多数是稳定型的,非稳定型的极少见。在 T淋巴细胞染色体畸变分析方面,不同距离的两组出现的稳定型畸变(19.6%,22.1%)或非稳定型畸变(2.0%,2.2%)的发生率几乎一致。592个异常中期细胞断裂点的位置呈现规律性的趋向,存活者也出现 B 淋巴细胞的染色体畸变,33—50%的细胞系为异常核型,结果提示某些异常核型的 B 淋巴细胞在体内正在形成一种克隆。由这些细胞遗传学表现可以认为,从接受照射到白血病发生,似乎包含着染色体质变与量变的许多阶段。     

Stimulation of cyclic adenosine monophosphate formation by the novel vasorelaxant peptide adrenomedullin in cultured rat mesangial cells

This study was conducted to compare the tensile bond strength at the two interfaces of the "sandwich technique". 48 hours after the specimens were tested, using Hounsfield tensometer. Load was gradually applied on to the specimen till the bond at the interface failed. The load at which the bond failed was recorded and analysed for statistical significance. From the present study it can be concluded that the bond between glass ionomer and dentine is better than the bond between glass ionomer and composite resin.     

Facial expression recognition of a speaker using front-view face judgment, vowel judgment, and thermal image processing

For facial expression recognition, we selected three images: (i) just before speaking, (ii) speaking the first vowel, and (iii) speaking the last vowel in an utterance. In this study, as a pre-processing module, we added a judgment function to distinguish a front-view face for facial expression recognition. A frame of the front-view face in a dynamic image is selected by estimating the face direction. The judgment function measures four feature parameters using thermal image processing, and selects the thermal images that have all the values of the feature parameters within limited ranges which were decided on the basis of training thermal images of front-view faces. As an initial investigation, we adopted the utterance of the Japanese name “Taro,” which is semantically neutral. The mean judgment accuracy of the front-view face was 99.5% for six subjects who changed their face direction freely. Using the proposed method, the facial expressions of six subjects were distinguishable with 84.0% accuracy when they exhibited one of the intentional facial expressions of “angry,” “happy,” “neutral,” “sad,” and “surprised.” We expect the proposed method to be applicable for recognizing facial expressions in daily conversation.     

Hydrodynamic vertical rotation method for a single cell in an open space

Rotation of a single cell is an indispensable cell manipulation technique for genetic studies and clinical applications. Conventional contact manipulation methods for rotation of a cell use complex control systems and tools, while conventional non-contact manipulation methods have limitations regarding the operating space or range of the rotated cell size. Here, we report on a convenient, non-contact, and open space method for a wide range of single cell sizes (micrometer scale to millimeter scale) rotating in a vertical plane (out-of-plane) of an open space. This method uses a vertical microscale recirculation zone for capturing and rotating the cell. We fabricated a micro-orifice on the surface of a microfluidic chip to generate the micro-recirculation zone and then carried out experiments on vertical rotations of Xenopus oocyte, embryoid body, brine shrimp oocyte, and zebrafish oocyte using this chip. We demonstrated the rotation of four types of cells in the vertical plane between the air–liquid interface and the top surface of the microfluidic chip; then, we conducted a simulation to analyze the dynamics of the vertical rotation of the Xenopus oocyte qualitatively. Our results indicated rotation speed of the four types of cells was controllable by the micro-recirculation zone. The size and density of oocytes also affected the process of capturing and rotation. We expect this method opens new research opportunities in three-dimensional cell manipulation, imaging, and analysis.     

A fast response and gamma-insensitive neutron detector based on parallel-plate avalanche counter

The use of the parallel-plate avalanche counter for slow-neutron counting is described. The choice of a suitable neutron converter is discussed on the basis of Monte Carlo simulation, and some experimental results are shown. Excellent gamma-insensitivity, high rate capability, possibility of construction in large sensitive area and low production cost are among the promising features of this neutron detector.     

Growth of LiF/LiBaF<Subscript>3</Subscript> eutectic scintillator crystals and their optical properties

Li-containing materials can be applied as neutron scintillators, and LiBaF₃ can discriminate neutron and gamma rays. Moreover, LIF/LiBaF₃ can have higher cross section of thermal-neutron capture compared with LiBaF₃. In this study, LiF (82.5 mol%) and (Ba_1?x RE _x )F₂ (17.5 mol%, RE = Ce and Eu, x = 0.002) eutectic crystals, LiF/RE:LiBaF₃, were grown by the micropulling down method with different pulling rates (growth rate) in order to observe the eutectic structure. Lamellar microstructure was formed for each pulling rate. LiF/Ce:LiBaF₃ excited by 5.5-MeV alpha rays had a broad peak at ~350 nm corresponding to 5d–4f transition of Ce³⁺. On the other hand, LiF/Eu:LiBaF₃ had two scintillation processes; a sharp emission was originated from ⁶P_7/2 → ⁸S_7/2 transitions in the 4f electronic configuration of Eu²⁺ at 360 nm, and a broad one was attributed to Eu²⁺ trapped exciton recombination at 400–450 nm. Since scintillation light was observed for these materials, these scintillators are sensitive to neutrons.